Living creatures, which are arranged in an organization by a hierarchic system of non-living matter, are combinations of syst eachms within other. Each level contains unique systemic arrangements. However, in different levels, each organization works in a wonderful and perfect harmony with other levels so that the living creature survive. As a result, the responsibilities entrusted its structure and function(s) are not interrupted.
Who created such miraculous entities?
At present, many highly educated people and scientists maintain there should be a creator who knows and has the power to design of all these perfectly working organizations. Starting from an atom's particles, this systemic structure consisting of atoms, molecules, macromolecules, cell organelles, cells, tissues, organs, systems, and finally a living creature exists in all ecological balances on Earth. Without seeing the impact of such a wide and large power, it is not logical to expect that all that we see in creation is the result of unconscious nature and thus conclude that everything occurred by blind happenstance.
We remain alive because millions of cells work together. Each maintains its life by being perfectly divided into units and having complex mechanisms within its structure. Each unit has unique features. When these units come together, large and unpredictable new features might occur. For example, hydrogen is flammable and oxygen is burning, but when they join together to form water, there is no fire.
A cell, which consists of electrons, protons, and neutrons, might function differently according to its location in the body. When cells are combined with each other, they form cell groups that acquire such characteristics as flexibility, movement, reproduction, and nerve transmission. We know that all such body units as cells, tissues, and organs have a perfect integrated system. And yet it is still unclear how they combine and carry out the functions necessary to make eyes, the brain, bones, muscles, and so on, all of which are composed mainly of carbon, hydrogen, oxygen, nitrogen, and phosphate.
In short, many scientists are very curious about how brain tissues can perform hundreds of different functions (e.g., hearing, thinking, and feeling) even though they are composed of atoms.
For the last two decades, scientists have been working on small molecules, DNA, RNA, and proteins, in order to shed some light to the unknown aspects of life. The Human Genome Project (HUGO) is one of the largest projects and is scheduled to be finished by 2005. Its goal is to sequence the cell's genetic material, which presumably numbers some 100,000 genes, and explain each one's function(s). However, so far only 10,000 to 20,000 are known. And this despite the fact that scientists have spent centuries learning how molecules are formed and what kind of force drives the atoms to form molecules!
Several famous foundations, among them Yale University, New York's Cold Harbor Laboratory, and Germany's Max Planc Institute, have been researching questions related to the body's structure. For example, how did it occur in such a small living cell, even though its building mechanism and systems are far more complicated than the system, which is all around us? How are dead cells expelled and replaced by new ones without disrupting any system's continued functioning.
In short, living creatures still hold many secret--so many, in fact, that despite recent technological advancements many unknown subjects remain. What we know may be compared to a drop of water and the ocean.
DNA and genes
Excluding blood cells, one body contains millions of cells. For instance, there are approximately 5 million white blood cells within 1 mm3 of blood. Each cell has a nucleus (its brain), and each nucleus contains genetic codes (DNA). Such genetic information as hair and eye color, bodily height, and blood group is hidden within the folded DNA and packed onto 46 human chromosomes distributed. If we could unfold the DNA package within each cell, we would get a 2-meter long DNA strain.
In addition, each chromosome contains small DNA units (genes). Scientists estimate that there are about 100,000 genes, each of which has a unique function, in a human genome. For instance, there are globin (the major component of hemoglobin) genes on chromosomes 11 and 16, and individual genes on the X chromosome that enable us to see colors. Another gene on the X chromosome synthesizes a dystrophine protein within our muscles, other genes on chromosome 6 control ferine metabolism, another gene on chromosome 7 controls the ion traffic, and so on.
When we look at a gene's structure, we realize that it they only are encoded by four letters (nucleotides): adenine (A), guanine (G), cytosine (C), and timin (T). The different orders of these four nucleic acids enable the gene to encode billions of protein amino acid combinations. The smallest gene, globin, is composed of 60,000 letters; the longest gene, distrophine, is composed of 2.4 million letters. If any letter is missing or is in the wrong place within the globin gene (e.g., AATG_ letter missing or AATTC letter change instead of AATGC), the ensuing point mutation, deletion, or insertion within the original order causes serious and incurable genetic diseases.
Many mutations occur within the functional parts of the 100,000 genes; however, they are instantly (10-10 second) repaired by the DNA 's repair mechanism. If not, serious diseases might occur. Interestingly, not all mutations cause genetic diseases, for while one mutation could be common within one human population, it might not occur so frequently within another one. Amazingly, our genes, composed of billions of letters (but only from A, T, C, and G) and always work in a harmony and collaboration so that our body can survive in a perfect manner. Therefore, spontaneous mutations or breakdowns are instantly repaired and old cells are replaced by new ones so quickly that we are not even aware of it.
In sum, the Creator has given each living entity a perfect and aesthetic body that functions in a most amazing manner. The only thing we have to do is thank the Creator for His generosity. That is perhaps the easiest task for us to do.
- Thomas Gelehrter-William Wilkins, Principle of Medical Genetics Scientific American (January 1998).